Writing instrument



FIG. 1 is a perspective showing my new design;

FIG. 2 is a right side elevational view of FIG. 1;

FIG. 3 is a left side elevational view of FIG. 1;

FIG. 4 is a rear elevational view of FIG. 1;

FIG. 5 is a front elevational view of FIG. 1;

FIG. 6 is a top plan view of FIG. 1;

FIG. 7 is a bottom plain view of FIG. 1; and,

FIG. 8 is a perspective view showing the ball-point pen element retracted (not visible). 

The ornamental design for a writing instrument, as shown and described. 